Comments do not seem to create this error. I managed to get the error to generate by not having a [space] between my select statement and the next command. For example while using the syntax for select all: "Select*" - Error, "Select *" - No error. The missing space appears to confuse Alteryx but not an SQL interface. In addition I placed comments before the select statement using various syntax methods, I also placed them throughout the SQL editor and the comments did not appear to change the Error message result at all.